This invention relates generally to fuel nozzles and, more specifically, to a variable area fuel nozzle for use in a gas turbine engine.
A gas turbine engine operates from start up to maximum power and requires relatively low fuel flowrates to relatively high fuel flowrates, respectively. Various types of fuel nozzles are known in the prior art for suitably providing fuel to a combustor of the engine. Conventional fuel nozzles include, for example, those types defined as simplex, duplex, dual orifice, variable port, spill or return, and pintle. These various conventional fuel nozzles are of varying complexity and performance, and attempt to provide optimum fuel atomization and flow characteristics under the various power settings of the engine.
Furthermore, a conventional fuel nozzle is typically designed for operating with only a particular class of fuels. However, in a land vehicle gas turbine engine, for example, the ability to operate using alternate fuels can be desirable; for example, a vehicular engine capable of operating on liquid fuels such as diesel or gasoline. However, the use of gasoline in a vehicular engine having conventional fuel nozzles can result in boiling of the fuel under low-power operation when the engine is relatively hot. Boiling of the fuel would adversely affect operation of the engine.
Accordingly, an object of the present invention is to provide a new and improved fuel nozzle for a gas turbine engine.
Another object of the present invention is to provide a relatively simple fuel nozzle having only one moving part.
Another object of the present invention is to provide a variable area fuel nozzle.
Another object of the present invention is to provide a fuel nozzle having a variable restriction discharge port for maintaining fuel pressure above the fuel vapor pressure for preventing boiling thereof.